In certain industrial applications there is a need for alloys which possess high rupture strength, high corrosion resistance and high oxidation resistance at elevated temperatures. Among such applications is the glass or mineral fiber industry where filaments are produced by passing a molten mineral material, for example glass, through the foraminous walls of a chamber which is adapted for rotation at high speeds (the chamber being known as a spinner). The filaments are emitted through the fiberizing orifices in the walls due to the centrifugal action of the rotating spinner. Such spinners are typically operated, at temperatures on the order of about 2050.degree. F. and rotation speeds on the order of 2050 RPM.
The advantages of being the low cost producer in any industry are enormous. Typically increased production or reduced costs in one area results in poor performance or increased cost in another area. Many ways exist to reduce costs in the production of glass fibers. Higher spinner rotational speeds increase production, but decrease spinner life. Stronger and more corrosion-resistant alloys help attain higher spinner speeds, but usually cost more.
Additional cost savings can be realized by fiberizing low cost batch formulations. But these have higher viscosities than normally used for glass wool insulation. The higher viscosities require higher fiberizing temperatures which in turn reduce spinner life.